Analysing nano-objects

Abstract

Methods and apparatus for analysis of nano-objects using wide-field bright field transmission techniques are described. Such methods may comprise acquiring a plurality of images of a sample comprising a plurality of nano-objects using bright field illumination via a continuously variable spectral filter, and identifying a nano-object within the sample in the plurality of images, wherein the position of the nano-object changes between images. Using data extracted from the plurality of images, an extinction cross-section of the identified nano-object may be quantitatively determined.

Description

FIELD OF INVENTION[0001]The present invention relates to methods of analysing nano-objects, in some examples using wide-field illumination techniques.BACKGROUND[0002]In some examples, a nano-object may be an object with at least one dimension smaller than the wavelength of interrogating light, which may be around 1 micron. In some examples, the method of analysis of nano-objects is a method of analysis of nanoparticles. Nanoparticles are objects with all dimensions of about 100 nm or less. The term nano-object may be used to refer to objects with at least one dimension of about 100 nm or less, and can include, for example, lithographic structures or carbon nanotubes, and nano-particles.[0003]In wide-field microscopy, a sample may be illuminated with light having a relatively broad spectrum and the transmission of the light through the sample is observed. However, for some types of samples, such techniques may suffer from low contrast.[0004]The interaction of light with different cla...

AI Technical Summary

Benefits of technology

The patent describes a method for measuring nano-objects on a substrate or in suspension in a carrier fluid. The method involves immobilizing the nano-objects on the substrate and moving the substrate relative to the imaging apparatus to capture multiple images. These images can be analyzed to determine the extinction cross-section of the nano-objects. This allows for the measurement of the particle-induced transmission change. The method also addresses the issue of short-range roughness caused by the shift of the image relative to the substrate. To slow down the movement of the nano-objects, the method suggests restricting their motion by increasing the viscosity of the carrier fluid or applying a singular value decomposition (SVD) to remove the drift associated with the imaging apparatus. Overall, this patent provides a more accurate, efficient, and flexible method for measuring nano-objects.

Problems solved by technology

However, for some types of samples, such techniques may suffer from low contrast.

However, current techniques for particle characterisation may be inaccurate, time consuming and / or expensive.

However, cross-section values—especially for scattering—can be difficult to quantify experimentally.

Currently available approaches tend to be complex and are generally suited to academic, rather than commercial, environments (an example may include laser-based techniques such as spatial modulation spectroscopy).

Some techniques, such as dark-field micro-spectroscopy, do not provide quantitative results and as such scattering cross-sections of nano-objects are rarely measured quantitatively and results are typically presented in arbitrary units.

Images